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Re: AW: OT: new Macbook wíthOUT Firewire :(



Rainer Thelonius Balthasar Straschill wrote:
> Per, you wrote:
> 
> 
>>it fully sufficient. I would think different though if I was up to 
>>making multi track recordings, as when recording twenty mic inputs at 
>>one go. But for everything else FW 400 is as good as FW 800.
> 
> 
> I'm a little bit curious about this bandwidth issue for firewire when 
>used
> for digital audio. Now if I understand this correctly, one of the big
> plusses of FireWire over, say, USB2, is that it works extremely well
> (meaning: low overhead) for streams.
> 
> Now if we assume you record twenty mic inputs, and if we furthermore 
>assume
> you record them in 24/96, then simple math gives us a data rate of 20
> (channels) * 96000 (samples per second) * 24 (bits per sample) = 44Mbit/s
> (rounded up). With a data rate of 400 MBit/s with FW400, this shouldn't 
>be a
> problem? What am I missing here?
> 
>       Rainer

As far as I can briefly see - nothing more than maybe forgetting some 
protocol packet overhead.  This was approx the same conclusion on the 
referred NG.

Not wanting to start a discussion about sample rate, but..
Again, on rec.audio.pro, it was mostly agreed that sample rates above 
44.1 or 48 doesn't yield anything, other than you her the drive more ;)
I'll look for a link to that discussion..

Personally, I choose 48 Khz over 44.1 Khz for reasons that outboard gear 
often use this clockrate, so interfacing/wordclock is easier, and 
reportedly some plugins have issues with either slow/fast sample rate.

At these sample rates the math looks even nicer, so even if adding a few 
overlooked speed/protocol issues, I'd say the ability to handle enough 
simultaneous channels for at least a minor/home studio should be enough 
- provided the maybe missing link is in place: that the actual 
interfaces and drivers works as intended per the firewire specs, and the 
PC/Mac interface sits in a well-designed chipset on a good mobo.
I guess everyone knows about inadequite/crappy interfaces/drivers..

-- 
rgds,
van Sinn